초록 ▼

A nuclear fuel rod has an elongated hollow cladding tube with a pair of end plugs and fuel pellets contained in the tube and extending between the end plugs. All pellets are composed of fissile material having a single enrichment. The pellets are provided in an axial stack having a length slightly l

A nuclear fuel rod has an elongated hollow cladding tube with a pair of end plugs and fuel pellets contained in the tube and extending between the end plugs. All pellets are composed of fissile material having a single enrichment. The pellets are provided in an axial stack having a length slightly less than the distance between the end plugs such that when the tube is disposed in a vertical orientation the stack of pellets at a lower end rests on the lower end plug and at an upper end is spaced from upper end plug by a gap. The gap is devoid of any structure restraining the stack from movement toward the upper end plug. The pellets in the stack are provided in an arrangement of axial regions which includes a pair of first opposite end axial regions and second and third tandemly-disposed middle axial regions between the first axial regions. The pellets in the first opposite end axial regions are identical in number and have annular configurations with an annulus of a first void size. Pellets in the second axial region have annular configurations with an annulus of a second void size smaller than the first void size of the annulus of pellet in the first axial regions. Pellets in the third axial region have solid configurations.

대표청구항 ▼

A fuel rod for use in a nuclear reactor fuel assembly, said fuel rod comprising: (a) an elongated hollow cladding tube; (b) a pair of end plugs connected to and sealing said cladding tube at opposite ends of thereof; and (c) an axial stack of fuel pellets contained in and extending between said end

A fuel rod for use in a nuclear reactor fuel assembly, said fuel rod comprising: (a) an elongated hollow cladding tube; (b) a pair of end plugs connected to and sealing said cladding tube at opposite ends of thereof; and (c) an axial stack of fuel pellets contained in and extending between said end plugs at said opposite ends of said tube, all of said fuel pellets contained in said tube being composed of fissile material being enriched above the level of natural enrichment; (e) said fuel pellets in said stack thereof being provided in an arrangement of axial regions, said arrangement of axial regions including a pair of first axial regions defined respectively at said opposite ends of said pellet stack adjacent to said respective end plugs, said pellets in said first axial regions being identical in number and having annular configurations with an annulus of a first void size, said arrangement of axial regions also including another axial region defined between said first axial regions, some of said pellets in said another axial region having solid configurations.